From: Eric Hodel <drbrain@...7.net>
Date: 2006-11-30T14:39:05+09:00
Subject: Re: Why doesn't Timeout work with String#=~

On Nov 29, 2006, at 0924 , Rob Biedenharn wrote:

> # I ran into trouble running a test on the result of a spell- 
> checking action
> # with a combination of a poorly formed regular expression and  
> having a third
> # misspelled word in the test phrase.  It was taking a LONG time (not
> # completed overnight!) so I thought I'd put a timeout around the  
> call so even
> # a truly gastly expression would be halted after some reasonalbe  
> amount of
> # time.
> #
> # However, it appears that the regular expression match with =~  
> doesn't get
> # interrupted by the timeout.  Is this expected?  I found a thread  
> about
> # timeout and syscalls
> # (http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/ 
> 178726) that
> # says that syscalls are interrupted which seems to imply that  
> things like
> # String#=~ ought to timeout also.
> #
> # Here's a "minimal" test that pulls the actual response out (so I  
> don't have
> # to try and recreate a string that will cause the regexp to churn  
> for a
> # long while).

Timeout uses threads and threads can only be switched when evaluating  
ruby.

String#=~ is written in C and can't be interrupted by ruby's thread  
scheduler.

-- 
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net

I LIT YOUR GEM ON FIRE!